Subject: [CCAMP] my review of draft-izh-ccamp-flexe-fwk

From: Daniele Ceccarelli <[email-masked]>
Date: Thu, 17 Jan 2019 14:12:21 +0000

Authors,

I reviewed draft-izh-ccamp-flexe-fwk. Please find below my comments.

*	Figure 1: I don't understand the figure. So far the main topic is
the fact that MAC rate and PHY rate do not necessarily map 1:1 but now I
don't understand what this reference model means. Can you add some text?
*	Section 4: you jump directly to the requirement without describing
what the framework is. I would expect a section before section 4 that
describes what you want to achieve, and then requirements. The direction
we're having lately from the IESG is that requirements not necessarily need
to be published. You can take them out in a separate document that we can
adopt but then not publish or keep in a section of this document and the we
put them in appendix, as you prefer.
*	- You start talking directly about the requirement of supporting the
creation of a flexE group and the only description of a flexE groups is 3
lines in the terminology. The section described above is really needed.
*	Section 5. As above. This needs to be introduced somehow. Moreover I
agree with the creation of the FlexE group, but does GMPLS configure
clients?
*	"Set up of a higher layer LSP that requires to be run over a FlexE
infrastructure."this is something that already exists. Whether an LSP is
created over a FlexE, an optical trail or a classical Eth link is
independent on the underlay technology.
*	"5.1.  Types of LSPs in a FlexE capable network. " isnt' the FlexE
the underlay with respect to the LSP? You might talk about procedures for
setting up LSPs in a FlexE network, not types of LSP.
*	Moreover if FlexE groups and clients are already preconfigured we're
in a classical non FlexE scenario, right?
*	Instead of starting straight with a multilayer control plane I would
talk about just the control plane of FlexE and the eventually talk about all
the possible solutions for the combination of control planes (FlexE and
LSP), confederated, multilayer etc.
*	Probably section 6 is a good candidate for the intro section missing
before section 4 (the one I was describing above)
*	6.2.1 I would spend more time describing the architecture rather
than jumping directly to signaling and routing. Describe the data plane and
what you want to achieve, before jumping into what needs to be advertised
and what needs to be signaled.
*	Section 7. What is a flexE LSP? I expect to read this in the new
section (architecture/framework?)

BR

Daniele

---

From: Loa Andersson <[email-masked]>
Date: Fri, 18 Jan 2019 20:48:14 +0800

Daniele,

On 2019-01-17 22:12, Daniele Ceccarelli wrote:> Authors,
 >     the fact that MAC rate and PHY rate do not necessarily map 1:1 but
 >     now I don't understand what this reference model means. Can you
 >     add some text?

Thanks for a careful review, much appreciated. As for your first point
I have a working copy pre-07 and have added the following text to the
Introductio:

    This document is a framework for the network control plane signaling
    and routing extensions required to establish FlexE links (FlexE
    Groups (PHY) and FlexE CLients (MAC)).  FlexE Links may interconnect
    customer edge devices (CE to CE), CE to provider edge devices (PE),
    PE to PE, or devices at the edge to devices in the core (PE to P) or
    devices in the core (P to P).

    Any pair of neighboring L2 and L3 device that support FlexE
    interfaces may be interconnected P2P using a FlexE link (PHY and
    MAC).  Further a device that terminates a FlexE link MUST be able to
    extract either the L2 or L3 payload and switch on the appropriate
    level, i.e.  Ethernet, MPLS or IP.  It should be noted that any type
    of switching is outside is out of scope for the FlexE specification.

    FlexE CE devices may typically be L3 routers or other devices that
    use FlexE at layers 1 and 2 to provide point-to-point connectivity
    between each other.

    Thus this draft considers the cases in which the two peer FlexE
    devices are:

    o  interconnecting two parts of a customer network (CE to CE).

    o  at the edge of the customer network (CE) and the close edge of the
       provider network (PE to CE).

    o  opposite edges of the FlexE capable network (PE tom PE).

    o  at the edge of the FlexE network PE interconnected to a provider
       device (PE to P).

    o  interconnecting two provider devices (P to P).

    This list of deployment cases will help identify the GMPLS control
    plane (i.e.  routing and signaling) extensions that may be required
    to support establishment of FlexE services.

And changed the reference model like this;

4.  FlexE Reference Model

    The figure below gives a simplified FlexE reference model.

                                     +-----+
                                     |  P  |
                          ...........+-+-+-+.............
                 n x PHY  .    n x     | |    m x       .
                          .  crunched  | |  crunched    .
        +----+      +-----+    PHYs    | |    PHYs      +-----+    +----+
        | CE +------+ PE1 +------------+ +--------------+ PE2 +----+ CE |
        +----+      +-----+                             +-----+    +----+
                          .                             .
        +----+   p x PHY  .                             .          +----+
        | CE +-----------------------------------------------------+ CE |
        +----+            .                             .          +----+
                          .       OTN Network           .
                          .                             .
                          ...............................

        +----+   q x PHY                                           +----+
        | CE +-----------------------------------------------------+ CE |
        +----+                                                     +----+

                   Legend: m, n, p and q indicates how many PHYs
                           there are in a FlexE Group

Would this be a step in the right direction??

/Loa

<snip - rest of the point<, will try to respond to those asap >

> 
> BR
> 
> Daniele
> 
> 
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-- 

Loa Andersson                        email: [email-masked]
Senior MPLS Expert
Bronze Dragon Consulting             phone: +46 739 81 21 64